Abstract

Both type I and type V hyperlipoproteinemia are characterized by hyperchylomicronemia (1). In type I hyperlipoproteinemia levels of no other serum lipoproteins are increased, whereas in type V hyperlipoproteinemia very low density lipoprotein levels are also elevated. Recognized complications of both disorders include episodes of abdominal pain, acute pancreatitis, splenomegaly, and splenic infarction (1). We report a middle-aged patient with the type V phenotype who was unusual because she had pancytopenia secondary to hypersplenism, a complication previously believed not to occur with splenomegaly due to hyperchylomicronemia (1). She also had a profound deficiency of lipoprotein lipase activity in both postheparin